The plane crashed into a grassy field and burst into flames early Sunday, killing 49 of the 50 people aboard. The only survivor, first officer James M. Polehinke, who was piloting the plane, was in critical condition.
Investigators were looking into whether the runway lights or a repaving project a week ago played any role in the pilot choosing the wrong runway. Both the old and new taxiway routes cross over the shorter runway.
"It's slightly different than it used to be," said Charlie Monette, president of Aero-Tech flight school at the airport. "Could there have been some confusion associated with that? That's certainly a possibility."
CBS News correspondent Bob Orr reports the cockpit voice recorder and air traffic control tapes leave no doubt the pilots were lost on the wrong runway. Flight 5191 was cleared to take off on runway 22, a lighted and long 7,000-foot strip. But, for some reason, the pilots turned onto the shorter and unlighted runway 26.
National Transportation Safety Board member Debbie Hersman said the voice recorder showed the pilots were talking about the absence of lights on the runway, but they didn't report it to the control tower. A light rain was falling Sunday, and it was still dark around 6 a.m. when the plane crashed.
The shorter runway at Blue Grass Airport is for daylight operation only, and its lights haven't worked since October 2001. The long runway has lights in the center, but only the ones along the side were working, according to a notice the Federal Aviation Administration sent to airlines.
All discussions between the plane and the control tower were about a takeoff from the main strip, which is 7,000 feet long, Hersman said. It was unclear whether the Comair pilots had been to the airport since the changes to the taxi route.
Air traffic controllers are not responsible for making sure pilots are on the right runway, said John Nance, a pilot and aviation analyst. "You clear him for takeoff and that's the end of it," Nance said.
The construction changes momentarily confused veteran pilot Lowell Wiley two days before the Comair crash. He nosed his plane down the same taxiway that he had taken for years until hitting a barricade.
"It was a total surprise," said Wiley, who adjusted course and got onto the correct runway. He now understands why the Comair pilot might have headed down a runway 1,500 feet too short to make a proper takeoff.
Investigators used a high truck to simulate the pilots' view of the runways and taxiways in their efforts to determine why the jet turned onto a shorter runway.
Authorities also planned to prepare a full report on the pilots, including what they did on and off duty for several days before the crash, the worst U.S. plane disaster since 2001.
Two other flights departed from Blue Grass Airport without problems, but somehow Flight 5191 ended up on the shorter runway instead — a cracked surface about 3,500 feet long that forms an X with the main runway and is meant only for small planes. Aviation experts say the CRJ-100 would have needed 5,000 feet to get airborne.
Hersman said the NTSB has not yet interviewed the lone controller on duty at the time. Other information retrieved from the cockpit voice recorder indicates preflight preparations were "consistent with normal operations."
The FAA said a second air traffic controller would be added to the weekend overnight shifts at the airport beginning next weekend. Agency spokeswoman Laura Brown declined to give a reason for the decision.
The bodies of the 49 victims were taken to the medical examiner's office in Frankfort for autopsies. Kentucky's chief medical examiner, Dr. Tracy Corey, was uncertain how long it will take to identify all the victims. Comair had not released a passenger manifest and said it was seeking permission from victims' families to release the names.
The crash in Lexington was the deadliest in the U.S. since Nov. 12, 2001, when American Airlines Flight 587 plunged into a residential neighborhood in New York City, killing 265 people, including five on the ground.